1. Field of the Invention
The present invention relates to a manipulator system capable of installing a capturing device at the tip of an arm included in an industrial robot or the like and replacing working tools.
In particular, the present invention relates to a manipulator system suitable to the work in a severe environment such as a space environment.
2. Description of the Prior Art
Upon manipulators working in space, various specifications such as the area of the working range and high precision working have been imposed. In addition, constraints such as the weight limit at the time when a vehicle is launched into space.
In order to meet these demands, there has been proposed a space station having an improved manipulator as described in JP-A-61-30387, for example. In this space station, a high precision, small-sized manipulator (a small arm) is mounted on the tip of a large-sized manipulator (a large arm) having a wide working range or they are arranged so as to be individually controlled. As a result, a wide range of conveyance work and high precision construction, maintenance and inspection work can be performed in space stations.
Since a small arm is serially connected to the tip of a large arm or they are individually controlled, however, the above described manipulator has problems described below.
(1) A complex work such as a work in which one end is held while the other end is rotated cannot be easily performed.
(2) Since the coupling of two manipulators is serial connection, there is a limit in expanding the operation region.
(3) Since the small arm is fixed to a stand or the like, mechanical and thermal protection in the space different from that of the large-sized manipulator is required, uneconomical results being caused.
(4) In case of serial coupling, force is propagated through the whole. When the load is increased, therefore, the stiffness of the whole must be raised, resulting in a largely increased weight.
(5) Since only one tip is always present, tools must be frequently replaced, resulting in a lowered efficiency.